Scientists at the University of Massachusetts Amherst report in the current issue of Small that they have genetically designed a new strain of bacteria that spins out extremely thin and highly conductive wires made up solely of non-toxic, natural amino acids.
Researchers led by microbiologist Derek Lovley say the wires, which rival the thinnest wires known to man, are produced from renewable, inexpensive feedstocks and avoid the harsh chemical processes typically used to produce nanoelectronic materials.
Lovley says, “New sources of electronic materials are needed to meet the increasing demand for making smaller, more powerful electronic devices in a sustainable way.” The ability to mass-produce such thin conductive wires with this sustainable technology has many potential applications in electronic devices, functioning not only as wires, but also transistors and capacitors. Proposed applications include biocompatible sensors, computing devices, and as components of solar panels.
This advance began a decade ago, when Lovley and colleagues discovered that Geobacter, a common soil microorganism, could produce “microbial nanowires,” electrically conductive protein filaments that help the microbe grow on the iron minerals abundant in soil. These microbial nanowires were conductive enough to meet the bacterium’s needs, but their conductivity was well below the conductivities of organic wires that chemists could synthesize.
“As we learned more about how the microbial nanowires worked we realized that it might be possible to improve on Nature’s design,” says Lovley. “We knew that one class of amino acids was important for the conductivity, so we rearranged these amino acids to produce a synthetic nanowire that we thought might be more conductive.”
The trick they discovered to accomplish this was to introduce tryptophan, an amino acid not present in the natural nanowires. Tryptophan is a common aromatic amino acid notorious for causing drowsiness after eating Thanksgiving turkey. However, it is also highly effective at the nanoscale in transporting electrons.
“We designed a synthetic nanowire in which a tryptophan was inserted where nature had used a phenylalanine and put in another tryptophan for one of the tyrosines. We hoped to get lucky and that Geobacter might still form nanowires from this synthetic peptide and maybe double the nanowire conductivity,” says Lovley.
The results greatly exceeded the scientists’ expectations. They genetically engineered a strain of Geobacter and manufactured large quantities of the synthetic nanowires 2000 times more conductive than the natural biological product. An added bonus is that the synthetic nanowires, which Lovley refers to as “biowire,” had a diameter only half that of the natural product.
“We were blown away by this result,” says Lovley. The conductivity of biowire exceeds that of many types of chemically-produced organic nanowires with similar diameters. The extremely thin diameter of 1.5 nanometers (over 60,000 times thinner than a human hair) means that thousands of the wires can easily be packed into a very small space.
The added benefit is that making biowire does not require any of the dangerous chemicals that are needed for synthesis of other nanowires. Also, biowire contains no toxic components. “Geobacter can be grown on cheap renewable organic feedstocks so it is a very ‘green’ process,” he notes. And, although the biowire is made out of protein, it is extremely durable. In fact, Lovley’s lab had to work for months to establish a method to break it down.
“It’s quite an unusual protein,” Lovley says. “This may be just the beginning” he adds. Researchers in his lab recently produced more than 20 other Geobacter strains, each producing a distinct biowire variant with new amino acid combinations. He notes, “I am hoping that our initial success will attract more funding to accelerate the discovery process. We are hoping that we can modify biowire in other ways to expand its potential applications.”
The Latest on: Nanoelectronic materials
via Google News
The Latest on: Nanoelectronic materials
- Designer-defect clamping of ferroelectric domain walls for more-stable nanoelectronicson January 22, 2020 at 9:42 am
Engineered defects in ferroelectric materials provides key to improved polariaztion stability ... Improved stability a significant step forward for domain-wall nanoelectronic data storage." ...
- Superior polarization retention through engineered domain wall pinningon January 17, 2020 at 2:38 am
Ferroelectric materials possess a spontaneous polarization that is switchable by an electric field. Robust retention of switched polarization is critical for non-volatile nanoelectronic devices based ...
- Two-Step Open BAA: Functional Materials and Applications (AFRL/RXA)on January 4, 2020 at 4:00 pm
The following research areas are of interest: Nanoelectronic materials (Agile RF Electronic Materials and Integrated Photonics & Opto-Electronic Materials and Processing) Soft Matter Materials ...
- Advanced 2D Materials for Quantum and Bio Nanotechnologyon November 22, 2019 at 11:56 pm
We plan to fabricate quantum nanoelectronic devices for quantum and biosensing applications employing advanced 2D materials. Novel device functionality will be achieved by interfacing complex ...
- New Fundamental Nanoelectronic Device Based on HgTe, a Topological Insulatoron October 29, 2019 at 9:59 am
A revolutionary discovery has been made by physicists at the University of Würzburg who have developed a fundamental nanoelectronic device based ... Topological insulators are materials with ...
- Application of air-sensitive semiconductors in nanoelectronics: 2-D semiconductor gallium selenide in encapsulated nanoelectronic deviceson September 21, 2019 at 5:00 pm
The study was published in Semiconductor Science and Technology. One of the promising areas of modern materials science is the study of two-dimensional (2D) materials, i.e. thin films consisting of ...
- Excitonic Dark States Shed Light on TMDC Atomic Layers: Berkeley Lab Discovery Holds Promise for Nanoelectronic and Photonic Applicationson September 10, 2019 at 5:00 pm
Using two-photon excitation spectroscopy, the researchers probed monolayers of tungsten disulfide, one of the most promising of 2D materials, and found evidence for the existence of excitonic dark ...
- Nano-Sandwiching Improves Heat Transfer, Prevents Overheating in Nanoelectronicson September 12, 2018 at 11:56 am
Sandwiching two-dimensional materials used in nanoelectronic devices between their three-dimensional silicon bases and an ultrathin layer of aluminum oxide can significantly reduce the risk of ...
- Colloidal nanoelectronic state machines based on 2D materials for aerosolizable electronicson July 22, 2018 at 5:00 pm
A previously unexplored property of two-dimensional electronic materials is their ability to graft electronic functionality onto colloidal particles to access local hydrodynamics in fluids to ...
- Focus: Taking Temperature in 2Don February 2, 2018 at 9:22 am
Electron microscopy can produce nanometer-scale maps of the thermal expansion of 2D materials, which may be important for the development of nanoelectronic devices. A heated response. An electron ...
via Bing News